U.S. patent application number 10/329958 was filed with the patent office on 2004-08-19 for method and apparatus for mitigating radio frequency interference between transceiver systems.
Invention is credited to Chinn, Gordon, Durrant, Randolph L., Kardach, James P., Monroe, Robert L., Rajamani, Krishnan.
Application Number | 20040162106 10/329958 |
Document ID | / |
Family ID | 32849320 |
Filed Date | 2004-08-19 |
United States Patent
Application |
20040162106 |
Kind Code |
A1 |
Monroe, Robert L. ; et
al. |
August 19, 2004 |
Method and apparatus for mitigating radio frequency interference
between transceiver systems
Abstract
Methods and apparatus are disclosed for mitigating radio
frequency interference between transceiver systems within an
electronic device.
Inventors: |
Monroe, Robert L.; (Colorado
Springs, CO) ; Durrant, Randolph L.; (Colorado
Springs, CO) ; Rajamani, Krishnan; (San Diego,
CA) ; Chinn, Gordon; (San Jose, CA) ; Kardach,
James P.; (Saratoga, CA) |
Correspondence
Address: |
MARSHALL, GERSTEIN & BORUN LLP
6300 SEARS TOWER
233 S. WACKER DRIVE
CHICAGO
IL
60606
US
|
Family ID: |
32849320 |
Appl. No.: |
10/329958 |
Filed: |
December 26, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10329958 |
Dec 26, 2002 |
|
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10218401 |
Aug 14, 2002 |
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Current U.S.
Class: |
455/552.1 |
Current CPC
Class: |
H04W 88/06 20130101 |
Class at
Publication: |
455/552.1 |
International
Class: |
H04M 001/00 |
Claims
What is claimed is:
1. A method comprising: providing channel information from a first
transceiver system to a second transceiver system via a first path
of a communication link, the channel information being indicative
of a radio channel associated with the first transceiver system,
and the first and second transceiver systems being in the same
electronic device; and providing priority information from the
second transceiver system to the first transceiver system via a
second path of the communication link, the priority information
being indicative of a priority activity associated with the second
transceiver system to use the radio channel.
2. A method as defined in claim 1, wherein providing channel
information from a first transceiver system to a second transceiver
system via a first path of a communication link comprises providing
channel information from the first transceiver system to the second
transceiver system via a first path of one of a wire interface and
a wireless link between the first transceiver system and the second
transceiver system.
3. A method as defined in claim 1, wherein providing channel
information from a first transceiver system to a second transceiver
system via a first path of a communication link comprises providing
channel information from a transceiver system operating in
accordance with the Institute of Electrical and Electronic
Engineers (IEEE) 802.11b communication protocol and a transceiver
system operating in accordance with the Bluetooth communication
protocol.
4. A method as defined in claim 1, wherein providing channel
information from the first transceiver system to the second
transceiver system via a first path of the communication link
comprises providing a four-bit code indicative of the radio channel
from the first transceiver system to the second transceiver system
via the first path of the communication link.
5. A method as defined in claim 1, wherein providing channel
information from the first transceiver system to the second
transceiver system via a first path of the communication link
comprises providing channel information indicative of a direct
sequence spread spectrum (DSSS) channel from the first transceiver
system to the second transceiver system via the first path of the
communication link, the DSSS channel being a radio channel
currently in use by the first transceiver system.
6. A method as defined in claim 1, wherein the providing channel
information from the first transceiver system to the second
transceiver system via a first path of the communication link
comprises providing a host controller interface (HCI) command
indicative of a frequency hopping spread spectrum (FHSS) channel
from the first transceiver system to the second transceiver system
via the first path of the communication link, the FHSS channel
being a radio channel operable by the second transceiver system for
communication.
7. A method as defined in claim 1, wherein providing channel
information from the first transceiver system to the second
transceiver system via a first path of the communication link
comprises providing channel information from transceiver systems
disposed within one of a laptop computer, a handheld computer, a
cellular telephone, and a personal digital assistant (PDA).
8. A method as defined in claim 1, wherein providing priority
information from the second transceiver system to the first
transceiver system via a second path of the communication link
comprises providing priority information indicative of one of a
device discovery, a connection establishment, a connection
maintenance, and a human interface device (HID) profile via the
second path of the communication link.
9. A method comprising: providing a channel data signal from a
first transceiver system to a second transceiver system via a first
path of a communication link, the channel data signal including
information indicative of a radio channel associated with the first
transceiver system, and the first and second transceiver systems
being in the same electronic device; providing a channel clock
signal from the second transceiver system to the first transceiver
system via a second path of the communication link to retrieve the
information indicative of the radio channel; providing a first
priority signal from the first transceiver system to the second
transceiver system via a third path of the communication link to
use the radio channel in response to a priority activity associated
with the first transceiver system; and providing a second priority
signal from the second transceiver system to the first transceiver
system via a fourth path of the communication link to use the radio
channel in response to a priority activity associated with the
second transceiver system.
10. A method as defined in claim 9, wherein providing a
communication link having at least four paths between a first
transceiver system and a second transceiver system comprises
providing one of a wire interface and a wireless link between the
first transceiver system and the second transceiver system.
11. A method as defined in claim 9, wherein providing a
communication link having at least four paths between a first
transceiver system and a second transceiver system comprises
providing a communication link having at least four paths between a
transceiver system operating in accordance with the Institute of
Electrical and Electronic Engineers (IEEE) 802.11b communication
protocol and a transceiver system operating in accordance with the
Bluetooth communication protocol.
12. A method as defined in claim 9, wherein providing a channel
data signal from the first transceiver system to the second
transceiver system via a first path of the communication link
comprises providing a four-bit code indicative of the radio channel
from the first transceiver system to the second transceiver system
via the first path of the communication link.
13. An electronic device comprising: a communication link having at
least two paths; a first transceiver system, the first transceiver
system being configured to provide channel information associated
with a radio channel via a first path of the communication link,
and the radio channel is associated with the first transceiver
system; and a second transceiver system in communication with the
first transceiver system via the communication link, the second
transceiver system being configured to provide priority information
indicative of a priority activity associated with second
transceiver system via a second path of the communication link.
14. An electronic device as defined in claim 13, wherein the
communication link is one of a wire interface and a wireless
link.
15. An electronic device as defined in claim 13, wherein the first
transceiver system is a transceiver system operating in accordance
with Institute of Electrical and Electronic Engineers (IEEE)
802.11b communication protocol, and the second transceiver system
is a transceiver system operating in accordance with Bluetooth
communication protocol.
16. An electronic device as defined in claim 13, wherein the
channel information includes a four-bit code indicative of the
radio channel.
17. An electronic device as defined in claim 13, wherein the
channel information includes a host controller interface (HCI)
command indicative of a radio channel operable by the second
transceiver system for communication.
18. An electronic device as defined in claim 13, wherein the
communication link comprises a third path and a fourth path,
wherein the first transceiver system being configured to transmit
priority information indicative of a priority activity associated
with the first transceiver system via the third path, and wherein
the second transceiver system being configured to transmit a clock
pulse via the fourth path to initiate transmission of channel
information from the first transceiver system.
19. An electronic device as defined in claim 13 is one of a laptop
computer, a handheld computer, a cellular telephone, and a personal
digital assistant (PDA).
20. In an electronic device including a first transceiver system
and a second transceiver system, a computer program comprising: a
first routine that directs a processor to provide channel
information from a first transceiver system to a second transceiver
system via a first path of a communication link having at least two
paths, the channel information being indicative of a radio channel
associated with the first transceiver system, the processor
operates in accordance with a computer program embodied on a
computer-readable medium; and a second routine that directs the
processor to provide priority information from the second
transceiver system to the first transceiver system via a second
path of the communication link, the priority information being
indicative of a priority activity associated with the second
transceiver system to use the radio channel.
21. A computer program as defined in claim 20, wherein the first
routine comprises a routine that directs the processor to provide
channel information from a first transceiver system to a second
transceiver system via a first path of one of a wire interface and
a wireless link.
22. A computer program as defined in claim 20, wherein the first
routine comprises a routine that directs the processor to provide
channel information from a transceiver system operating in
accordance with the Institute of Electrical and Electronic
Engineers (IEEE) 802.11b communication protocol to a transceiver
system operating in accordance with the Bluetooth communication
protocol via the first path of the communication link.
23. A computer program as defined in claim 20, wherein the first
routine comprises a routine that directs the processor to provide a
four-bit code indicative of the radio channel from the first
transceiver system to the second transceiver system via the first
path of the communication link.
24. A computer program as defined in claim 20, wherein the first
routine comprises a routine that directs the processor to provide a
host controller interface (HCI) command from the first transceiver
system to the second transceiver system via the first path of the
communication link, the HCI command being indicative of a radio
channel operable by the second transceiver system.
25. A computer program as defined in claim 20 further comprising: a
third routine that directs the processor to provide priority
information from the first transceiver system to the second
transceiver system via a third path of the communication link, the
priority information being indicative of a priority activity
associated with the first transceiver system; and a fourth routine
that directs the processor to provide a clock pulse from the second
transceiver system to the first transceiver system via a fourth
path of the communication link, the clock pulse being configured to
initiate transmission of channel information from the first
transceiver system to the second transceiver system via the first
path of the communication link.
26. A computer program as defined in claim 20, wherein the
electronic device comprises one of a laptop computer, a cellular
telephone, and a personal digital assistant (PDA).
27. A computer program as defined in claim 20, wherein the
computer-readable medium is one of paper, a programmable gate
array, application specific integrated circuit, erasable
programmable read only memory, read only memory, random access
memory, magnetic media, and optical media.
28. A system comprising: a communication link having at least two
paths; a first transceiver system, the first transceiver system is
to provide channel information associated with a radio channel via
a first path of the communication link, and the radio channel is
associated with the first transceiver system; and a second
transceiver system in communication with the first transceiver
system via the communication link, the second transceiver system is
to provide priority information indicative of a priority activity
associated with second transceiver system via a second path of the
communication link.
29. A system as defined in claim 28, wherein the communication link
is one of a wire interface and a wireless link.
30. A system as defined in claim 28, wherein the first transceiver
system is a transceiver system operating in accordance with
Institute of Electrical and Electronic Engineers (IEEE) 802.11b
communication protocol, and the second transceiver system is a
transceiver system operating in accordance with Bluetooth
communication protocol.
31. A system as defined in claim 28, wherein the channel
information includes a four-bit code indicative of the radio
channel.
32. A system as defined in claim 28, wherein the communication link
comprises a third path and a fourth path, wherein the first
transceiver system being configured to transmit priority
information indicative of a priority activity associated with the
first transceiver system via the third path, and wherein the second
transceiver system being configured to transmit a clock pulse via
the fourth path to initiate transmission of channel information
from the first transceiver system.
33. A system comprising: an antenna; a communication link having at
least two paths; a first transceiver system operatively coupled to
the antenna, the first transceiver system is to provide channel
information associated with a radio channel via a first path of the
communication link, and the radio channel is associated with the
first transceiver system; and a second transceiver system
operatively coupled to the antenna, the second transceiver system
is in communication with the first transceiver system via the
communication link, and the second transceiver system is to provide
priority information indicative of a priority activity associated
with second transceiver system via a second path of the
communication link.
34. A system as defined in claim 33, wherein the communication link
is one of a wire interface and a wireless link.
35. A system as defined in claim 33, wherein the first transceiver
system is a transceiver system operating in accordance with
Institute of Electrical and Electronic Engineers (IEEE) 802.11b
communication protocol, and the second transceiver system is a
transceiver system operating in accordance with Bluetooth
communication protocol.
36. A system as defined in claim 33, wherein the channel
information includes a four-bit code indicative of the radio
channel.
37. A system as defined in claim 33, wherein the communication link
comprises a third path and a fourth path, wherein the first
transceiver system being configured to transmit priority
information indicative of a priority activity associated with the
first transceiver system via the third path, and wherein the second
transceiver system being configured to transmit a clock pulse via
the fourth path to initiate transmission of channel information
from the first transceiver system.
38. A system comprising: a connecting means having at least two
paths; a first means for transmitting and receiving information,
the first means is to provide channel information associated with a
radio channel via a first path of the connecting means, and the
radio-channel is associated with the first transceiver system; and
a second means for transmitting and receiving information in
communication with the first means for transmitting and receiving
information via the connecting means, the second means is to
provide priority information indicative of a priority activity
associated with the second means via a second path of the
connecting means.
39. A system as defined in claim 38, wherein the first means is to
provide a four-bit code indicative of the radio channel from the
first means to the second means via the first path of the
connecting means.
40. A system as defined in claim 38, wherein the first means is to
provide a host controller interface (HCI) command indicative of a
frequency hopping spread spectrum (FHSS) channel to the second
means via the first path of the connecting means, the FHSS channel
being a radio channel operable by the second means for
communication.
41. A method comprising: providing a host controller interface
(HCI) command indicative of a frequency hopping spread spectrum
(FHSS) channel from a first transceiver system to a second
transceiver system via a first path of a wire interface, the FHSS
channel being a radio channel operable by the second transceiver
system for communication, and the first and second transceiver
systems being in the same electronic device; and providing priority
information from the second transceiver system to the first
transceiver system via a second path of the wire interface, the
priority information being indicative of a priority activity
associated with the second transceiver system to use the radio
channel.
42. A method as defined in claim 40, wherein providing an HCI
command from a first transceiver system to a second transceiver
system via a first path of a communication link comprises providing
an HCI command from a transceiver system operating in accordance
with one of the Institute of Electrical and Electronic Engineers
(IEEE) 802.11a, 802.11b and 802.11g communication protocols and a
transceiver system operating in accordance with the Bluetooth
communication protocol.
Description
[0001] CROSS REFERENCE TO RELATED APPLICATION
[0002] This application is a continuation-in-part (CIP) application
claiming priority from U.S. patent application Ser. No. 10/218,401,
entitled "Methods and Apparatus for Communicating via a Radio
Channel" filed Aug. 14, 2002.
TECHNICAL FIELD
[0003] The present disclosure relates generally to wireless
communication systems, and, more particularly, to a method and
apparatus for mitigating radio frequency interference between
transceivers.
BACKGROUND
[0004] Typically, standard local area network (LAN) protocols such
as Ethernet provide access to network resources through wired, land
line connections within a small geographic area (e.g., within an
office building). However, until recently, LANs were limited to the
conventional wired network connections. To increase mobility and
flexibility, the concept of wireless LANs (i.e., WLANs) has been
introduced. That is, WLANs provide convenient access to network
resources for portable computers (e.g., a laptop computer) and
handheld devices (e.g., a personal digital assistant (PDA)) both in
and out of the office via an access point. In particular, the
802.11 communication protocol developed by the Institute of
Electrical and Electronics Engineers (i.e., the IEEE 802.11
standard, IEEE std. 802.11-1997, published 1997) provides a
standard for WLANs for wireless transmissions using spread spectrum
radio frequency (RF) signals in the 2.4 gigahertz (GHz) Industrial,
Scientific, and Medical (ISM) frequency band. The 802.11
communication protocol offers wireless transmission at rates of
either one megabits per second (1 Mbps) or two megabits per second
(2 Mbps) to access wired LANs. Based on the 802.11 communication
protocol, the 802.11b communication protocol (i.e., IEEE 802.11b
standard, IEEE std. 802.11b-1999, published 1999, which is also
known as Wi-Fi or Wireless Ethernet) may extend the rate to 11
Mbps. The 802.11b communication protocol may also increase the RF
coverage up to approximately 500 feet. Despite enhancing the
ability of an electronic device to access a LAN (e.g., for web
browsing and e-mail), the 802.11b communication protocol may not be
optimal for establishing a wireless connection with devices in a
wireless personal area network (WPAN) such as computers, cellular
telephones, personal digital assistants (PDAs), and other
peripherals such as a mouse. That is, a disadvantage of the 802.11b
communication protocol is that a transceiver system (i.e., a radio
system) operating in accordance with the 802.11b communication
protocol may use an unnecessary amount of power to communicate with
WPAN devices.
[0005] It is widely known that the Bluetooth communication protocol
also uses short-range radio links to replace physical cables
connecting between portable and/or fixed electronic devices. Like
the 802.11b communication protocol, the Bluetooth communication
protocol also operates in the unlicensed 2.4 gigahertz (GHz) ISM
frequency band for short-range wireless connection between
computers, cellular telephones, cordless telephones, PDAs, local
area networks (LANs) and other peripherals such as printers, mice,
and facsimile machines. In particular, the Bluetooth communication
protocol may be used in wireless personal access networks (WPANs)
because it requires less power than the 802.11b communication
protocol. For example, a laptop notebook may be able to synchronize
with a PDA, to transfer files with a desktop computer and/or
another laptop notebook, to transmit or to receive a facsimile, and
to initiate a print-out of a document. Thus, an advantage of the
Bluetooth communication protocol is that the protocol is more
robust to communicate with WPAN devices than the 802.11b
communication protocol. However, a transceiver system operating in
accordance with Bluetooth communication protocol may not be able to
operate at sufficient power, range, and speed to access a LAN.
[0006] As noted above, both the 802.11b communication protocol and
the Bluetooth communication protocol operate in the 2.4 GHz ISM
frequency band. That is, the channels used by 802.11b transceiver
system and the Bluetooth transceiver system may interference with
each other. Thus, collision may occur when the 802.11 b transceiver
system and the Bluetooth transceiver system are communicating at
the same time (e.g., the Bluetooth transceiver system may cause
interference to the 802.11b transceiver system).
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic illustration of an example wireless
communication system.
[0008] FIG. 2 is a more detailed view of the electronic device of
FIG. 1.
[0009] FIG. 3 is a schematic illustration of example direct
sequence spread spectrum (DSSS) channels.
[0010] FIG. 4 is a schematic illustration of an example frequency
hopping spread spectrum (FHSS) channel in an interference zone.
[0011] FIG. 5 is a schematic illustration of another example FHSS
channel in the interference zone.
[0012] FIG. 6 is a schematic illustration of still another example
FHSS channel in the interference zone.
[0013] FIG. 7 is a schematic illustration of yet another example
FHSS channel in the interference zone.
[0014] FIG. 8 is a flowchart illustrating the operation of the
electronic device of FIG. 2.
[0015] FIG. 9 is a block illustration of a two-wire interface
between transceiver systems.
[0016] FIG. 10 is a timing illustration of communication of channel
information via the two-wire interface.
[0017] FIG. 11 is a table of four-bit channel codes indicative of
radio channels.
[0018] FIG. 12 is a timing illustration of communication of
priority information via the two-wire interface.
[0019] FIG. 13 is a timing illustration of a transceiver
system.
[0020] FIG. 14 is a block illustration of a four-wire interface
between transceiver systems.
[0021] FIG. 15 is a timing illustration of communication of
priority information via the four-wire interface.
DETAIL DESCRIPTION
[0022] Although the methods and apparatus disclosed herein are
particularly well suited for use with a laptop computer including a
transceiver system operating in accordance with the 802.11b
communication protocol and a transceiver system operating in
accordance with the Bluetooth communication protocol, persons of
ordinary skill in the art will readily appreciate that the
teachings herein are in no way limited to laptop computers. On the
contrary, persons of ordinary skill in the art will readily
appreciate that the teachings of this disclosure can be employed
with any electronic device such as a handheld computer, a cellular
telephone, and a personal digital assistant (PDA) regardless of the
wireless communication protocols it employs.
[0023] FIG. 1 is a schematic illustration of an example wireless
communication system 100. In the wireless communication system 100,
an electronic device 110 such as a portable computer may be in
communication with other portable or fixed electronic devices such
as, but not limited to, a laptop computer 130, a desktop computer
132, a personal digital assistant (PDA) 134, a cellular telephone
136, and a printer 138. Although in the illustrated example, the
electronic device 110 is shown as a portable computer, persons of
ordinary skill in the art will appreciate that the electronic
device 110 may be, but is not limited to, a laptop computer, a
notebook computer, a personal digital assistant (PDA), a cellular
telephone, etc. As used herein "portable computer" refers to any
computer (e.g., a laptop computer, a notebook computer) that is
designed to be carried by a person. The electronic device 110 may
also be in communication with a human interface device (HID) such
as, but not limited to, a mouse 140, a keyboard 142, and a monitor
144. Further, the electronic device 110 may be in communication
with an access point 150 operatively coupled to a local area
network (LAN) to access, for example, the Internet, the Intranet,
and other servers.
[0024] As explained in detail below, the illustrated electronic
device 110 generally includes a first transceiver system and a
second transceiver system operable for wireless communication with
other electronic devices or networks in a wireless personal access
network (WPAN) and a wireless local area network (WLAN). One
possible implementation of the electronic device 110 is shown in
FIG. 2. As shown in that figure, the electronic device 110
generally includes a processor 202, a memory 204, a first
transceiver system 210 and a second transceiver system 220. The
processor 202 is operatively coupled to the memory 204, which
stores a computer program as described in detail below or a set of
operating instructions for the processor 202. Accordingly, the
processor 202 executes the program or the set of operating
instructions such that the electronic device 110 operates to
provide the environments reflected in FIG. 1. The program or set of
operating instructions may be embodied in a computer-readable
medium such as, but not limited to, paper, a programmable gate
array, an application specific integrated circuit (ASIC), an
erasable programmable read only memory (EPROM), a read only memory
(ROM), a random access memory (RAM), a magnetic media, and an
optical media.
[0025] The processor 202 is also operatively coupled to the first
transceiver system 210 and the second transceiver system 220. The
first transceiver system 210 may be operatively coupled to the
second transceiver system 220 via a communication link 230. For
example, the first transceiver system 210 may be in communication
with the second transceiver system 220 via a communication bus. In
another example, the first transceiver system 210 may be directly
wired to the second transceiver system 220 (i.e., a hardwire link).
Alternatively, the communication link 230 may be a wireless link
such as a radio frequency link or an infrared link. Each of the
first and second transceiver systems 210, 220 may include, but is
not limited to, a transmitting unit generally shown as 212 and 222,
and a receiving unit generally shown as 214 and 224. The
transmitting unit 212 and the receiving unit 222 may be configured
as multiple units as shown in FIG. 2 or be configured as a single
(e.g., integral or unitary) unit.
[0026] As noted above, the first and second transceiver systems
210, 220 may provide wireless communication services to the
electronic device 110. To illustrate the concept of communicating
via a radio channel, the first transceiver system 210 may operate
in accordance with a first wireless communication protocol, and the
second transceiver system 220 may operate in accordance with a
second wireless communication protocol. For example, the first
wireless communication protocol may be, but is not limited to, the
Institute of Electrical and Electronics Engineers (IEEE) 802.11b
communication protocol (the IEEE standard 802.11b for "High Rate"
Wireless Local Area Network), and the second wireless communication
protocol may be, but is not limited to, the Bluetooth communication
protocol. Accordingly, the first transceiver system 210 may operate
in accordance with the IEEE 802.11b communication protocol
(hereinafter "802.11b transceiver system"), and the second
transceiver system 220 may operate in accordance with the Bluetooth
communication protocol (hereinafter "Bluetooth transceiver
system"). Both the 802.11b transceiver system 210 and the Bluetooth
transceiver system 220 may be operable to communicate with other
devices and/or networks via radio channels. Persons of ordinary
skill in the art will readily appreciate that the 802.11b
transceiver system 210 and the Bluetooth transceiver system 220 may
use well known direct sequence spread spectrum (DSSS) and frequency
hopping spread spectrum (FHSS) algorithms, respectively, to select
radio channels for communication.
[0027] Accordingly, to provide short range ad-hoc connections
between devices in WPANs and connections to WLANs, two transceiver
systems operating in accordance with different communication
protocols may be integrated into an electronic device. For example,
a laptop notebook may include two transceiver systems with one
transceiver system operating in accordance with the 802.11b
communication protocol (i.e., 802.11b transceiver system) and the
other transceiver system operating in accordance with the Bluetooth
communication protocol (i.e., Bluetooth transceiver system). The
802.11b transceiver system uses a direct sequence spread spectrum
(DSSS) modulation technique whereas the Bluetooth transceiver
system uses a frequency hopping spread spectrum (FHSS) modulation
technique. In particular, the DSSS modulation technique spreads
data transmissions across 22 MHz segments of the entire available
frequency band in a prearranged scheme. Within the 2.4 GHz
frequency band, the 802.11b communication protocol defines 14
"center frequency channels" with channels 1 through 11 supported
within the United States, and channels 12 through 14 supported
outside the U.S. In particular, channel 1 at 2.412 GHz, channel 6
at 2.437 GHz, and channel 11 at 2.462 GHz are the more commonly
used non-overlapping channels. Channels 1, 6, and 11 are spaced
apart by 25 MHz. The 802.11b communication protocol may also be
configured to provide six overlapping channels spaced 10 MHz apart.
Typically, the DSSS modulation technique uses one channel and
spreads data transmissions across a twenty-two megahertz band
(i.e., a bandwidth of 22 MHz). Further, the 802.11b transceiver
system may encode data with a code known only to certain 802.11b
transceiver systems so that data transmissions may not be as
susceptible for intruders to intercept and decipher. With FHSS
modulation technique, the Bluetooth transceiver system is
synchronized to hop from channel to channel in a predetermined
pseudorandom sequence known only to certain Bluetooth transceiver
systems. The Bluetooth communication protocol includes up to 79
narrow channels with each channel having a one megahertz band
(i.e., a bandwidth of 1 MHz in between 2.4 and 2.484 GHz).
Typically, the FHSS modulation technique uses a majority of the
channels and hops between the channels for data transmissions. As a
result, the 802.11b transceiver system may be used for WLAN
communication, and the Bluetooth transceiver system may be used for
WPAN communication.
[0028] A basic flow for scheduling communication via a radio
channel that may be applied with the electronic device 110 shown in
FIGS. 1 and 2 may start with the Bluetooth transceiver system 220
selecting a radio channel for communication (i.e., a selected radio
channel). As used herein "communication" refers to any transmission
and/or reception of a signal. For example, the selected radio
channel may be used by the Bluetooth transceiver system 220 for
transmitting a file to a desktop computer and/or receiving a
command from a mouse. Persons of ordinary skill in the art will
appreciate that selection of a radio channel may be implemented in
many ways. For example, the Bluetooth transceiver system 220 may
use a well known frequency hopping spread spectrum (FHSS),algorithm
to select the radio channel for communication (e.g., an FHSS
channel). The Bluetooth transceiver 220 may receive an 802.11b
operating signal from the 802.11b transceiver system via the
communication link 230. The 802.11b operating signal may include
channel information indicative of the DSSS channel such as, but not
limited to, a reference corresponding to a radio channel for
communication associated with the 802.11b transceiver system 210
(e.g., a DSSS channel), an operating mode of the DSSS channel
(e.g., active or inactive), and a priority level of communication
associated with the 802.11b transceiver system 210 (e.g., low or
high) via the DSSS channel. As used herein "DSSS channel" refers to
any radio channel selected by the 802.11b transceiver system 210 to
communicate with other electronic devices or networks in the
wireless communication system 100 such as an access point (one
shown as 150 in FIG. 1) or other 802.11b client via the ad hoc
mode. Thus, the reference corresponding to the DSSS channel may be,
but is not limited to, a letter, an alphanumeric character, and a
number such as channel 1, channel 6, and channel 11 of any well
known DSSS algorithm. The operating mode indicates whether the
802.11b transceiver system 210 is using and/or is intending to use
the DSSS channel for communication. The priority level indicates
whether the communication associated with the 802.11b transceiver
system 210 via the DSSS channel has higher priority over the
communication associated with the Bluetooth transceiver system 220
via the FHSS channel.
[0029] Based on the channel information provided by the 802.11b
transceiver system 210, the electronic device 110 (e.g., via the
Bluetooth transceiver system 220) determines whether the FHSS
channel may be available for communication associated with the
Bluetooth transceiver system 220 without causing radio interference
between the FHSS channel and the DSSS channel. That is, the
electronic device 110 determines whether the FHSS channel is in an
interference zone of the DSSS channel (i.e., the frequency band of
the FHSS channel is within, overlaps, adjacent to or substantially
proximate to the frequency band of the DSSS channel) based on the
reference corresponding to the DSSS channel. As noted above,
persons of ordinary skill in the art will appreciate that the
802.11b transceiver system may use a DSSS algorithm to select the
DSSS channel. Referring to FIG. 3, for example, the DSSS algorithm
may provide the 802.11b transceiver system with three
non-overlapping DSSS channels (i.e., channels, 1, 6, and 11)
generally shown as 310, 320, and 330. The three non-overlapping
channels are spaced 25 MHz apart in the 2.4 gigahertz (GHz)
Industrial, Scientific, and Medical (ISM) frequency band (i.e.,
between 2.4 and 2.484 GHz). Each of the three non-overlapping
channels has a bandwidth of 22 MHz. In particular, channel 1 at
2.412 GHz extends from 2.401 to 2.423 GHz (shown as 310), channel 6
at 2.437 GHz extends from 2.426 to 2.448 GHz (shown as 320), and
channel 11 at 2.462 GHz extends from 2.451 to 2.473 GHz (shown as
330). Alternatively, the 802.11b transceiver system may be
configured to operate any of the fourteen channels available for
the 802.11b communication protocol.
[0030] Persons of ordinary skill in the art will appreciate that
the Bluetooth transceiver system may use an FHSS algorithm to
select the FHSS channel. In particular, the FHSS algorithm may
provide the Bluetooth transceiver system with a radio channel
having a bandwidth of 1 MHz in the 2.4 GHz ISM frequency band for
communication. Thus, there may be radio interference between the
802.11b transceiver system and the Bluetooth transceiver system 220
because the FHSS channel may be in the interference zone of the
DSSS channel. Referring to FIG. 4, for example, the FHSS channel
410 extending from 2.406 to 2.407 GHz is within the DSSS channel
310. As a result, the FHSS 410 may be in the interference zone of
the DSSS channel 310. In another example, the FHSS channel 510
shown in FIG. 5 extends from 2.4225to 2.4235 GHz. The FHSS channel
510 may be in the interference zone of the DSSS channel 310 because
the FHSS channel 510 overlaps the DSSS channel 310 (i.e., from
2.4225to 2.423 GHz). As shown in FIG. 6, the FHSS channel 610
extends from 2.423to 2.424 GHz. Although, the FHSS channel 610 is
adjacent to the DSSS channel 310, the FHSS channel 610 may still be
in the interference zone of the DSSS 310 because marginal radio
interference may exist with the FHSS 610 being on the edge of the
DSSS channel 310. Further, marginal radio interference may exist
with the FHSS channel 710 being substantially proximate to the DSSS
channel 310 as shown in FIG. 7. As a result, the FHSS channel 710
may also be in the interference zone of the DSSS channel 310.
[0031] If the FHSS channel is not in the interference zone of the
DSSS channel (e.g., the FHSS channel does not overlap the DSSS
channel and the FHSS channel is not substantially proximate to the
DSSS channel) then the Bluetooth transceiver system 220 may operate
the FHSS channel to communicate with other electronic devices or
networks in the wireless communication system 100 such as a PDA
(one shown as 134 in FIG. 1). On the other hand, if the FHSS
channel is in the interference zone of the DSSS channel as
described above then the electronic device 110 may determine
whether the DSSS channel is active for communication associated
with the 802.11b transceiver system 210 based on the operation mode
of the DSSS channel. For example, the electronic device 110 may
determine whether the DSSS channel is active for communication
associated with the 802.11b transceiver system 210 if the frequency
band of the FHSS channel (shown as 410 in FIG. 4)is within the
frequency band of the DSSS channel 310.
[0032] When the FHSS channel is in the interference zone, but the
operation mode of the DSSS channel is inactive (i.e., the 802.11b
transceiver system 210 is not using and/or is not intending to use
the DSSS channel for communication), the Bluetooth transceiver
system 220 may use the FHSS channel for communication. In contrast,
when the operation mode of the DSSS channel is active (i.e., the
802.11b transceiver system 210 is using and/or is intending to use
the DSSS channel for communication), the electronic device 110 may
determine whether communication associated with the 802.11b
transceiver system 210 has priority over communication associated
with the Bluetooth transceiver system 220. When the communication
associated with the 802.11b transceiver system 210 has higher
priority than the communication associated with the Bluetooth
transceiver system 220, the Bluetooth transceiver system 220 may
suspend its communication via the FHSS channel. For example, the
Bluetooth transceiver system 210 may entirely abort its
communication via the FHSS channel or wait until the communication
associated with the 802.11b transceiver system 210 via the DSSS
channel is completed before using the FHSS channel to communicate
with other devices or networks in the wireless communication system
100.
[0033] If the communication associated with the Bluetooth
transceiver system 220 has higher priority than the communication
associated with the 802.11b transceiver system 210 then the
Bluetooth transceiver system 220 may transmit a Bluetooth operating
signal to the 802.11b transceiver system 210. In particular, the
Bluetooth operating signal may indicate that the communication
associated with the Bluetooth transceiver system 220 has higher
priority than the communication associated with the 802.11b
transceiver system 210. In response to the Bluetooth operating
signal, the 802.11b transceiver system 210 may suspend its
communication via the DSSS channel to avoid interference with the
communication associated with the Bluetooth transceiver system 220.
That is, the 802.11b transceiver system 210 may entirely abort its
communication via the DSSS channel or wait until the communication
associated with the Bluetooth transceiver system 220 via the FHSS
channel is completed to communicate via the DSSS channel again. As
a result, radio interference between the 802.11b transceiver system
210 and the Bluetooth transceiver system 220 may be mitigated.
[0034] One possible implementation of the computer program executed
by the electronic device 110 to provide the environments reflected
in FIG. 1 is illustrated in FIG. 8. Persons of ordinary skill in
the art will appreciate that the computer program can be
implemented in any of many different ways utilizing any of many
different programming codes stored on any of many tangible mediums
such as a volatile or nonvolatile memory or other mass storage
device (e.g., a floppy disk, a compact disc (CD), and a digital
versatile disc (DVD)). Thus, although a particular order of steps
is illustrated in FIG. 8, persons of ordinary skill in the art will
appreciate that these steps can be performed in other temporal
sequences. Again, the flow chart is merely provided as an example
of one way to program the electronic device 110 to communicate via
a radio channel to reduce interference between the first and second
transceiver systems 210, 220 within the electronic device 110.
[0035] Assuming that the electronic device 110 includes an 802.11b
transceiver system and a Bluetooth transceiver system as described
above, the Bluetooth transceiver system uses a spread spectrum
technique such as the FHSS algorithm to select a radio channel for
communication, i.e., an FHSS channel (block 810 of FIG. 8). Persons
of ordinary skill in the art will readily appreciate that the
802.11b transceiver system may use a well known direct sequence
spread spectrum (DSSS) algorithm to select a radio channel for
communication (i.e., a DSSS channel). At block 820, the Bluetooth
transceiver system also receives an 802.11b operating signal from
the 802.11b transceiver system via the wired communication link
230. The 802.11b operating signal includes channel information
indicative of the DSSS channel such as, but not limited to, a
reference corresponding to the DSSS channel that the 802.11b
transceiver system is using and/or is intending to use for
communication (e.g., a channel number), an operation mode of the
DSSS channel (e.g., active or inactive), and a priority level of
communication associated with the 802.11b transceiver system via
the DSSS channel (e.g., low or high).
[0036] Upon selection of the FHSS channel for communication and
reception of the 802.11b operating signal from the 802.11b
transceiver system via the wired communication link 230, the
electronic device 110 (e.g., via the Bluetooth transceiver system)
determines whether the FHSS channel is available for communication
associated with the Bluetooth transceiver system based on channel
information indicative of the DSSS channel.
[0037] To determine whether the FHSS channel is available for
communication, the electronic device 110 determines whether the
FHSS channel is in an interference zone of the DSSS channel (block
830). Persons of ordinary skill in the art will appreciate that
there are many ways for the electronic device 110 to determine
whether the FHSS channel is in an interference zone of the DSSS
channel as shown in FIGS. 4, 5, 6 and 7. For example, the
electronic device 110 may use a look-up table to determine whether
the FHSS channel is in the interference zone with the DSSS channel
based on the channel number of the DSSS channel. In another
example, the electronic device 110 may use hardware components such
as, but not limited to, a comparator, to determine whether the
bandwidth of FHSS channel is in the interference zone of the
bandwidth of the DSSS channel.
[0038] Referring back to FIG. 8, when the FHSS channel is not in
the interference zone of the DSSS channel, the Bluetooth
transceiver system may use the FHSS channel to communicate with
other electronic devices, human interface devices, access points,
etc. within the wireless communication system 100 (block 840). If
the FHSS channel is in the interference zone of the DSSS channel,
control proceeds to block 850. At block 850, the electronic device
110 (e.g., via the Bluetooth transceiver system) determines whether
the 802.11b transceiver system is using and/or is intending to use
the DSSS channel for communication (e.g., transmission and/or
reception of a signal by the 802.11b transceiver system) based on
the operating mode of the DSSS channel. When the electronic device
110 detects that the DSSS channel is inactive (i.e., the 802.11b
transceiver system is not using and/or is not intending to use the
DSSS channel), the Bluetooth transceiver system may use the
selected RF channel for communication as described above (block
840).
[0039] If the electronic device 110 detects that the DSSS channel
is active (i.e., the 802.11b transceiver system is using and/or is
intending to use the DSSS channel), control continues to block 860.
At block 860, the electronic device 110 determines whether
communication associated with the 802.11b transceiver system via
the DSSS channel has higher priority than the communication
associated with the Bluetooth transceiver system via the FHSS
channel. For example, a high priority communication associated with
the 802.11b transceiver system may be, but is not limited to, an
acknowledgement of a reception of data packets, a CTS
(clear-to-send) reception, and a beacon reception. When the
electronic device 110 detects that the communication associated
with 802.11b transceiver system via the DSSS channel has higher
priority (block 860), the electronic device 110 may determine
whether to suspend the communication associated with the Bluetooth
transceiver system via the FHSS channel until the 802.11b
communication is complete (block 870). For example, the Bluetooth
transceiver system may wait and delay its communication via the
FHSS channel (block 872). Alternatively, the Bluetooth transceiver
system may entirely terminate its communication via the FHSS
channel (block 874), and control returns to block 810 to select
another radio channel for communication.
[0040] If the electronic device 110 detects that the communication
associated with the Bluetooth transceiver system via the FHSS
channel has higher priority than the communication associated with
the 802.11b transceiver system via the DSSS channel, control
proceeds to block 880. At block 880, the Bluetooth transceiver
system may transmit a Bluetooth operating signal (i.e., a priority
signal) to the 802.11b transceiver system, and control continues to
block 840. The Bluetooth operating signal indicates that the
communication associated with the Bluetooth transceiver system via
the FHSS channel has priority over the communication associated
with the 802.11b transceiver system via the DSSS channel. A high
priority communication associated with the Bluetooth transceiver
system may be, but is not limited to, device discovery, connection
establishment, connection maintenance, and human interface device
(HID) profile. In response to the Bluetooth operating signal, the
802.11b transceiver system may delay or entirely terminate its
communication via the DSSS channel. As a result, radio interference
between the Bluetooth transceiver system and the 802.11b
transceiver system may be reduced by scheduling communication via
the FHSS channel and the DSSS channel.
[0041] As noted above, the 802.11b transceiver system 210 and the
Bluetooth transceiver system 220 may be operatively coupled to each
other via a communication link 230 (shown in FIG. 2). The
communication link 230 may be, but is not limited to, a wire
interface (e.g., a hardwire link) and a wireless link (e.g., a
radio link or an infrared link). The communication link 230 may
include a plurality of paths so that the transceiver systems (shown
as 210 and 220) may communicate with each other. To illustrate this
concept, the communication link 230 may be a two-wire interface 930
as shown in FIG. 9. In particular, the two-wire interface 930
includes a channel data line 940 and a channel clock line 950. The
802.11b transceiver system 210 may transmit a channel data signal
(shown as CHANNEL_DATA) via the channel data line 940 so that the
Bluetooth transceiver system 220 may receive channel information
from the 802.11b transceiver system 210. As described detail below,
channel information may be, but is not limited to, a four-bit code
indicative of a radio channel associated with the 802.11b
transceiver system 210. In response to the channel data signal from
the 802.11b transceiver system 210 via the channel data line 940,
the Bluetooth transceiver system 220 may transmit a channel clock
signal (shown as CHANNEL_CLK) via the channel clock line 950.
[0042] Referring to FIG. 10, for example, the Bluetooth transceiver
system 220 may monitor the channel data line 940 for CHANNEL_DATA.
Upon detecting a rising edge of CHANNEL_DATA (i.e., the beginning
of START BIT), the Bluetooth transceiver system 220 may start the
channel clock line 950 within a reaction time period T.sub.reaction
to sample CHANNEL_DATA with a clock pulse T.sub.clk--period. The
Bluetooth transceiver system 220 may sample CHANNEL_DATA at a
rising edge of T.sub.clk_high of the clock pulse T.sub.clk--period
(i.e., when CHANNEL_CLK goes to a high state at the beginning of
T.sub.clk--high). In particular, the clock pulse T.sub.clk--period
may include T.sub.clk--high and T.sub.clk--low. Accordingly, the
802.11b transceiver system 210 may prepare to transmit channel
information during T.sub.setup after a falling edge of
T.sub.clk--low of the clock pulse T.sub.clk--period (i.e., when
CHANNEL_CLK goes to a low state at the beginning of
T.sub.clk--low). The Bluetooth transceiver system 220 may transmit
four additional clock pulses to receive a four-bit code indicative
of a radio channel associated with the 802.11b transceiver system
210 (e.g., a radio channel currently in use by the 802.11b
transceiver system 210).
[0043] After the START BIT, the 802.11b transceiver system 210 may
transmit the channel number corresponding to the radio channel
currently in use by the 802.11b transceiver system 210 to the
Bluetooth transceiver system 220. For example, the channel number
may be a four-bit code, generally shown as Bit0, Bit1, Bit2, and
Bit3, transmitted by the 802.11b transceiver system 210. The
Bluetooth transceiver system 220 may transmit four clock pulses,
generally shown as Pulse0, Pulse1, Pulse2, and Pulse3, to read
Bit0, Bit1, Bit2, and Bit3, respectively. At the end of Bit3, the
802.11b transceiver system 210 may set CHANNEL_DATA to a low state
until it is ready to transmit new channel information to the
Bluetooth transceiver system 220.
[0044] Persons of ordinary skill in the art will readily recognize
that the 802.11b communication protocol defines 14 "center
frequency channels" (i.e., DSSS channels) within the ISM 2.4 GHz
frequency band. To illustrate the concept of a four-bit code to
represent channel information associated with the 802.11b
transceiver system, the scheme shown in FIG. 11 may be implemented.
As an example, the 0000 channel code may indicate that all channels
may be available to the Bluetooth transceiver system 220 for
communication. Accordingly, a priority signal from the Bluetooth
transceiver system 220, if any, may be ignored by the 802.11b
transceiver system 210.
[0045] Turning to the priority signal, the Bluetooth transceiver
system 220 may transmit the priority signal via the channel clock
line 950 when the channel clock line 950 is not used to obtain
channel information from the 802.11b transceiver system 210. That
is, the Bluetooth transceiver system 220 may use the channel clock
line 950 to transmit either the channel clock signal (shown as
CHANNEL_CLK in FIG. 10) or the priority signal. Because the 802.11b
transceiver system 210 has priority as a default, the Bluetooth
transceiver system 220 may use the priority signal to override the
default. The priority signal may include information associated
with a high priority communication such as, but not limited to,
device discovery, connection establishment, connection maintenance,
and human interface device (HID) profile. Referring to FIG. 12, for
example, the 802.11b transceiver system 210 may sample the channel
clock line 950 and receive the priority signal (shown as
BT_PRIORITY) from the Bluetooth transceiver system 220 at the
beginning of time period t1. In response to BT_PRIORITY being at a
high state, the 802.11b transceiver system 210 may suspend all
non-critical communication via the radio channel by the end of the
time period t1 (i.e., the time period t1 is the maximum time for
the 802.11b transceiver system 210 to react to the priority signal
from the Bluetooth transceiver system 220). The Bluetooth
transceiver system 220 may keep BT_PRIORITY at a high state for
time period t2. At the end of the time period t2, the 802.11b
transceiver system 210 may resume communication via the radio
channel (i.e., the time period t2 is the maximum amount of time for
the Bluetooth transceiver system 220 to transmit its priority
signal). For the duration of time period t3, BT_PRIORITY is at a
low state before going to a high state again. That is, the
Bluetooth transceiver system 220 waits through the time period t3
before it may transmit another priority signal to the 802.11b
transceiver system 210 via the channel clock line 950.
[0046] During transmission of the priority signal, the Bluetooth
transceiver system 220 may monitor the channel data line 940 for an
indication from the 802.11b transceiver system 210 of a channel
data signal. To receive the channel data signal, the Bluetooth
transceiver system 220 may delay and/or terminate the transmission
of the priority signal and prepare to receive the channel data
signal from the 802.11b transceiver system 210 via the channel data
line 940. Accordingly, the Bluetooth transceiver system 220 may
proceed to sample the channel data line 940 prior to receiving the
four-bit channel code as described above.
[0047] The Bluetooth transceiver system 220 may operate in a
variety of modes based on the channel data line 940 and a host
controller interface (HCI) command (shown as BT_HCI in FIG. 13).
For example, the HCI command may be, but is not limited to, an 80
bit code [0:79] to designate a FHSS channel operable by the
Bluetooth transceiver system 220 for communication. When the
channel data line 940 is at a low state, the Bluetooth transceiver
system 220 may be allowed to use any of the 79 FHSS channels
regardless of the HCI command (shown as mode 1). Here, the 802.11b
transceiver system 210 may be inactive (i.e., turned off or
operating in a power saving mode).
[0048] When the channel data line 940 is at a high state, however,
the Bluetooth transceiver system 220 may operate to avoid either
one of or all 14 radio channels operable by the 802.11b transceiver
system 210 (i.e., DSSS channels) based on the HCI command. In
particular, each parameter of the HCI command may all be at a high
state (i.e., BT_HCI (1, 1, 1 . . . 1, 1)) so that the Bluetooth
transceiver system 220 may avoid all of the DSSS channels because a
communication link associated with the 802.11b transceiver system
210, for example, may be lost (shown as mode 2). To reestablish
that communication link, the 802.11b transceiver system 210 may
need to select from all of the DSSS channels. Alternatively, the
HCI command may instruct to the Bluetooth transceiver system 220 to
avoid a particular DSSS channel (e.g., BT_H (1, 1, 0, 0 . . . 0, 1,
1 . . . 1)) because the DSSS channel, for example, may be currently
in use by the 802.11b transceiver system 210 (shown as mode 3).
[0049] Referring to FIG. 14, another example of the wired
communication link 230 is shown. The wired communication link 230
may be a four-wire interface 1430 including a channel data line
1440, a channel clock line 1450, a first priority line 1460, and a
second priority line 1470. The channel data line 1440 and the
channel clock line 1450 may operate similar to the channel data
line 940 and the channel clock line 950 as described above,
respectively. However, the Bluetooth transceiver system 220 may not
use the channel clock line 1450 to transmit the priority signal.
Instead, the second priority line 1470 may be used to relay the
priority signal (i.e., BT_PRIORITY) from the Bluetooth transceiver
system 220 to the 802.11b transceiver system 210 in a similar
fashion as shown in FIG. 12. In turn, the 802.11b transceiver
system 210 may also transmit a priority signal (i.e.,
802.11b_PRIORITY) to the Bluetooth transceiver system 220 via the
first priority line 1460.
[0050] In particular, the Bluetooth transceiver system 220 may
receive the priority signal (shown as 802.11b_PRIORITY) from the
802.11b transceiver system 210 at the beginning of a time period t4
as shown in FIG. 15. Responsive to 802.11b_PRIORITY being at a high
state, the Bluetooth transceiver system 220 may suspend all
non-critical communication via the radio channel by the end of the
time period t4 (i.e., the time period t4 is the maximum time for
the Bluetooth transceiver system 220 to react to the priority
signal from the 802.11b transceiver system 210). The 802.11b
transceiver system 210 may keep 802.11b_PRIORITY at a high state
for time period t5. At the end of time period t5, the Bluetooth
transceiver system 220 may resume communication via the radio
channel (i.e., the time period t5 is the maximum time for the
802.11b transceiver system 210 to transmit its priority signal).
For the duration of time period t6, BT_PRIORITY is at a low state
before going to a high state again. That is, the 802.11b
transceiver system 210 may wait through the time period t6 before
it may transmit another priority signal to the Bluetooth
transceiver system 220 via the first priority line 1460.
[0051] As a result, the 802.11b transceiver system 210 may either
communicate a radio channel currently in use by the 802.11b
transceiver system 210 to the Bluetooth transceiver system 220 so
that the Bluetooth transceiver system 220 may avoid all
non-critical communication via the radio channel or indicate that
no radio channel is currently in use by the 802.11b transceiver
system 210 so that the Bluetooth transceiver system 220 may
communicate via the radio channel.
[0052] Although much of the above discussion has focused on
reducing radio interference between a transceiver system operating
in accordance with 802.11b communication protocol and a transceiver
system operating in accordance with Bluetooth communication
protocol, persons of ordinary skill in the art will appreciate that
transceiver systems operating in accordance with other
communication protocols may be used within a wireless communication
system or an electronic device such as 802.11 a and 802.11g
communication protocols.
[0053] Many changes and modifications to the embodiments described
herein could be made. The scope of some changes is discussed above.
The scope of others will become apparent from the appended
claims.
* * * * *